Search

Lessons (14)

• DSA Interview Patterns Cheat Sheet

  Map any coding-interview problem to the right technique in seconds. Keyword triggers, a decision flowchart, complexity tables …

• Two Pointers & Sliding Window

  … add the element entering on the right, remove the one leaving on the left](/img/dsa/sliding-window …

• Stacks & Queues

  … a ticket counter (first in, first out)](/img/dsa/stack-queue.svg) - Stack (LIFO — Last In, First Out …

• Hash Maps & Sets

  … lookups jump straight to the right place](/img/dsa/hash-map.svg) Operation Array (unsorted) Hash map / Set …

• Linked Lists

  … each node holds a value and an arrow to the next node](/img/dsa/linked-list.svg) js …

• Binary Search

  … halves the search space at every step](/img/dsa/binary-search.svg) Items Linear search (worst) Binary search …

• Arrays & Strings

  … equally sized boxes side by side, reached instantly by index](/img/dsa/array-memory.svg) That's why …

• Trees & Binary Search Trees

  … root, parent, child, leaf, depth and height](/img/dsa/tree-vocabulary.svg) Word Meaning --- --- Root The top node …

• Heaps & Priority Queues

  … the same heap stored in an array](/img/dsa/heap.svg) The array trick Because the tree has …

• Recursion & Backtracking

  … each call handles a smaller version until the base case](/img/dsa/recursion-dolls.svg) Every recursive function …

• Graphs: BFS & DFS

  … vs adjacency matrix for the same graph](/img/dsa/graph-representations.svg) Adjacency list Adjacency matrix --- --- --- Memory O …

• Big-O Notation Made Simple

  … from excellent to terrible](/img/dsa/big-o-ladder.svg) Recognising complexity in code js // O(1): same …

• Sorting Algorithms

  … Different algorithms trade simplicity , speed and memory . ![How the main sorting algorithms compare](/img/dsa/sorting-compare.svg …

• Dynamic Programming

  … the ways to reach each step are the sum of the two steps below it](/img/dsa/dp …